Статті в журналах: "Voltage balancing module"

1

Peng, Faxiang. "Hierarchical Modular Battery Equalizer With Open-Loop Control and Mitigated Recovery Effect." CPSS Transactions on Power Electronics and Applications 6, no. 4 (December 2021): 310–19. http://dx.doi.org/10.24295/cpsstpea.2021.00029.

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In this manuscript, an advanced battery equalizer with open-loop control is proposed. This equalizer is based on a two-layer hierarchical modular architecture. The top stringto- module (S2M) layer consists of a half-bridge inverter and a voltage multiplier (VM) rectifier, and the bottom cell-to-cell (C2C) layer is implemented by bidirectional buck-boost units. Without state-of-charge (SOC) estimation, the battery charge can be automatically transferred from high-voltage cell-modules/cells to low-voltage ones. Only a pair of symmetrical pulse width modulation (PWM) driving signals with fixed switching frequency and duty cycle are required.This reduces the control complexity remarkably. Meanwhile, the balancing current of each balancing path naturally attenuates with the convergence of cell-module/ cell voltages. This ensures a fast balancing of cell-module/cell with large voltage mismatch. The battery-recovery-effect induced balancing error is also effectively mitigated. Moreover, simple control facilitates a simultaneous module and cell voltage balancing in static, charging, and discharging conditions. The operation principles are analyzed in detail. An experimental platform with eight series-connected batteries is built and tested. The measured results well validate the theoretical analysis. Both cell and module voltages automatically converge with clearly mitigated recovery effect.

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2

Liu, Van Tsai, and Jhih Rong Chen. "Balancing for Lead-Acid Batteries of Electric Motorcycles." Applied Mechanics and Materials 764-765 (May 2015): 491–95. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.491.

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For high-power applications such as electric motorcycles, batteries in series to provide the required voltage is fairly common. The 48V is 12V connected four cells in series for lead-acid batteries of electric motorcycles. After charging and discharging of lead-acid batteries several times, the voltages are often imbalance. Without proper protection, may cause an excessive discharge of lead-acid batteries for early damage. Therefore, lead-acid battery module requires a simple balance circuit to improve battery life in order to avoid over-voltage or under-voltage condition occurs. Energy balance circuit to improve lead-acid battery module matching problems, make the safety and cycle life of lead-acid batteries to improve. This research intends to complete balanced circuit design of lead-acid batteries.

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3

Chen, Hung-Cheng, Shin-Shiuan Li, Shing-Lih Wu, and Chung-Yu Lee. "Design of a Modular Battery Management System for Electric Motorcycle." Energies 14, no. 12 (June 14, 2021): 3532. http://dx.doi.org/10.3390/en14123532.

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This paper proposes a modular battery management system for an electric motorcycle. The system not only can accurately measure battery voltage, charging current, discharging current, and temperature but also can transmit the data to the mixed-signal processor for battery module monitoring. Moreover, the system can control the battery balancing circuit and battery protection switch to protect the battery module charging and discharging process safety. The modular battery management system is mainly composed of a mixed-signal processor, voltage measurement, current measurement, temperature measurement, battery balancing, and protection switch module. The testing results show that the errors between the voltage value measured by the voltage measurement module and the actual value are less than 0.5%, about 1% under the conditions of different charging and discharging currents of 9 A and 18 A for the current measuring module, less than 1% for the temperature measurement module; and the battery balancing in the battery management system during the charging process. When the module is charged at 4.5 A for about 805 s, each cell of the battery has reached the balancing state. Finally, the testing results validate that the modular battery management system proposed in this paper can effectively manage the battery balancing of each cell in the battery module, battery module overcharge, over-discharge, temperature protection, and control.

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4

Pang, Yuqi, Gang Ma, Xunyu Liu, Xiaotian Xu, and Xinyuan Zhang. "A New MMC Sub-Module Topology with DC Fault Blocking Capability and Capacitor Voltage Self-Balancing Capability." Energies 14, no. 12 (June 9, 2021): 3409. http://dx.doi.org/10.3390/en14123409.

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A large number of modular multilevel converters (MMC) are connected to HVDC transmission systems nowadays. This paper aims at the short-circuit fault in the DC line of the HVDC transmission system and the problem of capacitor voltage imbalance in MMC, proposing a new type of MMC sub-module, which has both the DC fault self-clearing ability and the capacitor voltage self-balancing ability. This sub-module combines the topology of half bridge and full bridge. It uses the reverse capacitor voltage to forcibly turn off the conducting diode to block the fault current loop. At the same time, the two capacitances charge and discharge states are consistent by utilizing the operating mode of the sub-module. It is possible to directly achieve a self-balancing capacitor voltage without complex balancing voltage control. The MATLAB/Simulink simulation verifies the effectiveness of the DC fault blocking capability and capacitor voltage balance capability of the proposed sub-module.

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5

Syarif, Nirwan, Dedi Rohendi, Wulandari Sudarsono, and Wai Yin Wong. "Module Stabilizing of Biocarbon Based Electrochemical Capacitor." International Journal of Sustainable Transportation Technology 2, no. 1 (April 30, 2019): 32–38. http://dx.doi.org/10.31427/ijstt.2019.2.1.5.

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One of the disadvantages of the electrochemical capacitor (EC) or supercapacitor compared with batteries is its low specific energy. It limits of EC to meet the energy needs of the electrical-electronic devices, such as electric cars. To overcome those limitations, it needs a serial circuit to increase the voltage range, and parallel circuits to increase the storage capacity. Practically, the module that built from 2-6 pieces of 2.5V EC cells will not feasible to make the module with the voltage of 5-15 V. It was found that the voltage of the EC cell could decreases to about 2.0 V, so that the capacitance of the module significantly reduced. This paper reports the basic methods that can be applied to overcome these problems by using a stabilizing or balancing component. The balancing components used in this study were a resistor, a Zener diode, and a Schottky diode. Each component was attached to every EC cell. The influence of the Zener and Schottky diode was observed as a component of a blocking diode. The results showed that the use of a 100-ohm resistor and Zener diode reduces voltage peaks while the use of blocking diode modules leads to increased discharge time. In general, there was no significant change in the charging time, both with and without the balancing and blocking component.

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6

Bui, Thuc, Chang-Hwan Kim, Kyu-Ho Kim, and Sang Rhee. "A Modular Cell Balancer Based on Multi-Winding Transformer and Switched-Capacitor Circuits for a Series-Connected Battery String in Electric Vehicles." Applied Sciences 8, no. 8 (August 1, 2018): 1278. http://dx.doi.org/10.3390/app8081278.

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In this paper, a cell balancing topology for a series-connected Lithium-Ion battery string (SCBS) in electric vehicles is proposed and experimentally verified. In particular, this balancing topology based on the modular balancer consists of an intra-module balancer based on a multi-winding transformer circuit and an outer-module balancer based on a switched capacitor converter, both offering the potential advantages and over conventional balancing methods, including short equalization time, simple control scheme, elimination of voltage sensors. In addition, a number of cells in the SCBS can be easily extended in this circuit. Furthermore, a system structure and an operating principle of the proposed topology are analyzed and experimentally verified for three different cases. The voltages of all cells in the SCBS reached the balanced state regardless of the various arrangement of the initial voltage, where the energy efficiency of the circuit reached 83.31%. Our experimental realization of the proposed balancing topology shows that such a technique could be employed in electric vehicles.

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7

Li, Sheng Qing, Wen Xiang Xu, Wei Zhou Li, and Huan Yue Zeng. "DC Capacitor Voltage Balancing Control for Cascaded STATCOM." Applied Mechanics and Materials 325-326 (June 2013): 1221–24. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.1221.

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Through the DC side capacitor voltage unbalance problem of cascaded static synchronous compensator. Put through a theory of active voltage average distribution to balance DC capacitor voltage, using master slave controller to realize controlling requirements. The main controller calculates each phase AC side of H bridge required total active and reactive voltage and grid voltage phase information etc, The slave controller complete each cascade module for active voltage average distribution control. The simulation results show that the method is feasible and effective.

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8

Jing, Ji Min, Jing Ze Wang, and Yan Chao Ji. "Research on the Voltage Balance Strategy of Modular Multilevel Converter." Advanced Materials Research 1055 (November 2014): 157–60. http://dx.doi.org/10.4028/www.scientific.net/amr.1055.157.

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The modular multilevel converter (MMC) does not need clamping devices and multiple independent DC voltage source and has a modular structure which is easy to be extended to any level, share a DC side, easy to direct back to back four-quadrant operation and attracts widespread attention. Due to the use of sub-module MMC suspended on the DC side capacitor voltage divider provides synthetic AC output voltage required voltage level and therefore it is essential to the stable operation of the sub-module capacitor voltage balance of the MMC. In this paper, the factors affecting the MMC sub-module capacitor voltage balancing has been carried out a detailed analysis and this paper focuses on the nominal frequency erupted module capacitor voltage control strategies and the average low frequency sub-module capacitor voltage ripple suppression strategies.

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9

Saminathan S & Dr. Ranjithkumar K. "Multicarrier PWM Based Control of Modular Multilevel Inverter with Grid Connected Solar PV System." International Journal for Modern Trends in Science and Technology 7, no. 05 (May 27, 2021): 72–80. http://dx.doi.org/10.46501/ijmtst0705011.

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In this work, a new modular multilevel inverter topology is introduced for a single phase grid connected Photovoltaic system. This multilevel inverter use less number of switches to generate seven levels compared to other conventional multilevel inverters. This requires only one isolated dc source to operate. So it is suitable for renewable energy application. This inverter is designed by submodule configuration; each sub module contains two switches and one DC link capacitor. The sub modules will be added to the inverter depending on number of levels. The voltage balancing of DC link capacitor is carried out by Y matrix PWM technique. Because of Y matrix PWM technique, the inverter gets a self capacitor voltage balancing ability. So there is no need of external devices required for balancing the voltage of capacitor. A PLL for grid integration and LCL filter are designed and integrated with this inverter. The simulation of proposed system is carried out by MATLAB/SIMULINK and performance of THD is monitored as per standards

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10

Yu, Le, Xu Peng, and Shibin Gao. "Voltage-Balancing Strategy for Three-Level Neutral Point Clamped Cascade Converter under Sequence Pulse Modulation." Energies 12, no. 20 (October 10, 2019): 3829. http://dx.doi.org/10.3390/en12203829.

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In response to the unbalanced DC-port fault of three-level neutral point clamped cascaded converter (3LNPC-CC), a sequence pulse modulation (SPM) voltage-balancing strategy is proposed in this paper to balance DC-link voltage, not only within the module but also among modules. With the steps of carrier cascaded calculation and sequence pulse generator, the voltage level of cascaded modules would take a smooth transition. Then the limitation of the SPM strategy is calculated according to the law of volt-second balance and the law of energy conservation. The proposed strategy has the advantage of simple calculation and control stability. Simulation and experimental results show the superiority of the proposed strategy.

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11

Amin, Amin, Kristian Ismail, and Abdul Hapid. "Implementation of a LiFePO4 battery charger for cell balancing application." Journal of Mechatronics, Electrical Power, and Vehicular Technology 9, no. 2 (December 30, 2018): 81. http://dx.doi.org/10.14203/j.mev.2018.v9.81-88.

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Cell imbalance has always happened in the series-connected battery. Series-connected battery needs to be balanced to maintain capacity and maximize the batteries lifespan. Cell balancing helps to dispart energy equally among battery cells. For active cell balancing, the use of a DC-DC converter module for cell balancing is quite common to achieve high efficiency, reliability, and high power density converter. This paper describes the implementation of a LiFePO4 battery charger based on the DC-DC converter module used for cell balancing application. A constant current-constant voltage (CC-CV) controller for the charger, which is a general charging method applied to the LiFePO4 battery, is presented for preventing overcharging when considering the nonlinear property of a LiFePO4 battery. The prototype is made up with an input voltage of 43V to 110V and the maximum output voltage of 3.75V, allowing to charge a LiFePO4 cell battery and balancing the battery pack with many cells from 15 to 30 cells. The goal is to have a LiFePO4 battery charger with an approximate power of 40W and the maximum output current of 10A. Experimental results on a 160AH LiFePO4 battery for some state of charge (SoC) shows that the maximum battery voltage has been limited at 3.77 volt and maximum charging current could reach up to 10.64 A. The results show that the charger can maintain battery voltage at the maximum reference voltage and avoid the LiFePO4 battery from overcharging.

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12

Kang, Kyoung-Pil, Younghoon Cho, Ho-Sung Kim, and Ju-won Baek. "DC-Link Capacitor Voltage Imbalance Compensation Method Based Injecting Harmonic Voltage for Cascaded Multi-Module Neutral Point Clamped Inverter." Electronics 8, no. 2 (February 1, 2019): 155. http://dx.doi.org/10.3390/electronics8020155.

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In a three-level (NPC) converter, the voltage imbalance problem in the DC-link capacitors is major issue. This paper proposes the DC-link capacitor voltage imbalance compensation method, where a common offset voltage is injected for a multi-module NPC inverter. The offset voltage consists of a harmonic voltage and a voltage difference between the upper and lower capacitors. The proposed method does not require any hardware modification, so that it is easily implemented. In order to show the effectiveness of the proposed balancing method, theoretical analysis is provided to balance the voltages, and both the simulations and the experiments were carried out to show that the voltage difference of the DC-link was decreased by the proposed method.

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13

Zhao, Jianfei, Changjiu Kong, Tingzhang Liu, and Ruihua Li. "Research on an Auto-Optimized Capacitor Voltage Balancing Control Strategy of MMC SM for Renewable Energy HVDC Transmission System." Electronics 8, no. 1 (January 18, 2019): 104. http://dx.doi.org/10.3390/electronics8010104.

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The Modular Multilevel Converter (MMC) is one of the most attractive converter topologies in the High Voltage Direct Current (HVDC) transmission field. The latest widely used sorting method has a low algorithm complexity. It can effectively balance the sub-module (SM) capacitor voltages, but it would cause relatively high switching frequency and power loss. Aiming at the problem that the sub-module (SM) capacitor voltage sorting algorithm has a large switching loss due to the high switching frequency of the device, this paper proposes an auto-optimized capacitor voltage balancing control strategy. Firstly, the topology and operation principle of MMC are analyzed. Secondly, a SM capacitor voltage control method based on the dynamic deviation threshold is proposed. Considering the switch switching state of the SM and the difference between the voltages of each SM, the algorithm can obtain the dynamic deviation valve using the closed-loop control. The method can avoid the unnecessary repeated switching of the Insulated Gate Bipolar Transistor (IGBT) under the premise of ensuring that the capacitance voltages of the SMs are basically the same, which effectively result in reducing the switching frequency of the MMC SM and reducing the switching loss, thereby improving the operating efficiency of the system. Finally aiming at the proposed control strategy, the simulation and experimental verification are carried out which shows that the proposed algorithm can better control the system voltage deviation, reduce the switching loss of the system and improve the stability of the system.

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14

Abdelsalam, Mahmoud, Mostafa Marei, Sarath Tennakoon, and Alison Griffiths. "Capacitor voltage balancing strategy based on sub-module capacitor voltage estimation for modular multilevel converters." CSEE Journal of Power and Energy Systems 2, no. 1 (March 2016): 65–73. http://dx.doi.org/10.17775/cseejpes.2016.00010.

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15

Islam, Md Didarul, Reza Razzaghi, and Behrooz Bahrani. "Arm-Sensorless Sub-Module Voltage Estimation and Balancing of Modular Multilevel Converters." IEEE Transactions on Power Delivery 35, no. 2 (April 2020): 957–67. http://dx.doi.org/10.1109/tpwrd.2019.2931287.

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16

Lee, Junmin, Daewook Kang, and Jangmyung Lee. "A Study on the Improved Capacitor Voltage Balancing Method for Modular Multilevel Converter Based on Hardware-In-the-Loop Simulation." Electronics 8, no. 10 (September 21, 2019): 1070. http://dx.doi.org/10.3390/electronics8101070.

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In the power industry, hardware in-the-loop simulation (HILS) based on a real-time digital simulator (RTDS) is important technology for modular multilevel converter (MMC)-based high-voltage direct current (HVDC) power transmission. It is possible in real time to verify various fault situations that cannot be predicted by the software-in-the-loop simulation (SILS). This paper introduces the implementation methodology of sub-module (SM) capacitor voltage balancing for a MMC-HVDC physical control system based on field-programmable gate array (FPGA), which has the advantages of high-speed parallel operation and validates the reliability and accuracy of MMC-HVDC control when this control system is operated with RTDS. The characteristics of conventional capacitor voltage balancing methods, such as the nearest level control (NLC) with full sorting method, the NLC with reduced switching frequency method, and the tolerance band (TB) method, implemented on a physical control system based on this implementation methodology, are compared and analyzed. This paper proposes the improved capacitor voltage balancing method for MMC-HVDC transmission. Finally, the proposed capacitor voltage balancing method is compared with conventional methods to analyze performance in real-time to demonstrate that the proposed method is better than the conventional methods.

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17

Galván, Luis, Pablo J. Gómez, Eduardo Galván, and Juan M. Carrasco. "Optimization-Based Capacitor Balancing Method with Customizable Switching Reduction for CHB Converters." Energies 15, no. 6 (March 8, 2022): 1976. http://dx.doi.org/10.3390/en15061976.

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This paper presents a method for switching reduction in cascaded H-bridge converters. Given the wide applicability of this topology, it would be especially desirable to increase its efficiency with switching losses reduction techniques. Since this type of converter requires voltage balancing methods, several modulation methods consider the possibility of combining the balancing and switching reduction goals together. In this paper, a previously disclosed optimization-based balance method was modified further to consider the switching losses in its objective function. Each commutation was penalized in proportion to the phase current and the module voltage, thus avoiding commutations that would produce the most losses but tolerating low-losses commutations. The structure of the original method was maintained so that the algorithm could be applied with minimal change. The results show that it is possible to reduce the switching up to 14% without any noticeable drawback and up to 22% at the cost of a greater DC-link ripple. It is also possible to selectively reduce the effective switching frequency of only some modules, making it significantly low. This extends the adaptability of the converter, possibly allowing hybrid converters with modules of different transistor technologies.

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18

Wang, Yaoqiang, Yisen Yuan, Gen Li, Tianjin Chen, Kewen Wang, and Jun Liang. "A Generalized Multilevel Inverter Based on T-Type Switched Capacitor Module with Reduced Devices." Energies 13, no. 17 (August 26, 2020): 4406. http://dx.doi.org/10.3390/en13174406.

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Conventional multilevel inverters have problems in terms of their complicated expansion and large number of devices. This paper proposes a modular expanded multilevel inverter, which can effectively simplify the expansion and reduce the number of devices. The proposed inverter can ensure the voltage balancing of the voltage-dividing capacitors. The cascading of the T-type switched capacitor module and the step-by-step charging method of the switched capacitors enable the inverter to achieve high output voltage levels and voltage gain. In addition, the inversion can be achieved without the H-bridge, which greatly reduces the total standing voltage of the switches. The nine-level inverter of the proposed topology can be realized with only ten switches, obtaining a voltage gain that is two times larger. The above merits were validated through theoretical analysis and experiments. The proposed inverter has good application prospects in medium- and low-voltage photovoltaic power generation.

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19

Jiang, Bowen, and Yujing Liu. "A Hybrid Energy Storage System with Reconfigurability and Fast Equalisation." Power Electronics and Drives 7, no. 1 (January 1, 2022): 68–83. http://dx.doi.org/10.2478/pead-2022-0006.

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Abstract With the rapid growth of electric vehicles (EVs) in recent years, the research on their energy storage systems (ESSs) has also shown great popularity. A traditional ESS normally has a fixed configuration and uses a single type of energy storage unit. However, this traditional design has some limitations, such as low flexibility and high requirements to unit consistency. To solve these problems, a new hybrid energy storage system is proposed in this paper. The proposed ESS hybridises multiple lithium-ion battery modules and one supercapacitor module. By controlling the states of switches inside the ESS topology, module level reconfiguration can be achieved. Further, a DC/DC converter is also included in the ESS topology, which is connected to the supercapacitor module and can be used to ensure correct ESS output voltage. Reconfiguration and active balancing algorithms are also given based on the proposed ESS topology. Situations with and without bypassing the lithium-ion battery modules are both discussed in the algorithms. The proposed hybrid ESS is finally verified with simulations. The system model is built in the Simulink/MATLAB environment. Simulation results show that the lithium-ion modules with a lower state of charge values have higher priorities to be connected in parallel. Reconfiguration actions are able to balance all lithium-ion battery modules within one Worldwide Harmonised Light-Duty Vehicle Test Cycle (WLTC) simulation cycle while maintaining ESS output voltage within a correct range. Furthermore, the proposed hybrid ESS control algorithms remain valid when one lithium-ion battery module is manually bypassed during simulation.

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20

Toh, Chuen Ling, and P. C. Ooi. "Design a nine-level modular multilevel converter for DC railway electrification system." International Journal of Power Electronics and Drive Systems (IJPEDS) 11, no. 1 (March 1, 2020): 151. http://dx.doi.org/10.11591/ijpeds.v11.i1.pp151-159.

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<p>A recuperating converter is highly demanded in traction power substation to deliver the braking energy generated by a traction vehicle. Conventional voltage source inverter had been implemented in the traction power station. However, large ac line filters must be installed to improve the quality of ac voltages and currents. This paper proposes to install a nine-level Modular Multilevel Converter (MMC) as a recuperating converter. The main aim is to eliminate the need of ac line filters while producing good quality of ac voltage and current waveforms. The MMC is designed and modelled using MATLAB/Simulink Simulation tool. A centralized control of balancing all the sub-module capacitor voltage level is proposed with Third Harmonic Voltage Injection Level Shifted Pulse Width Modulation (THVI-LSPWM) technique. The simulation results prove that with the application of MMC, good quality of ac voltages and currents are being produced. The Total Harmonic Distortion indexes are found less than 3.5 % without using any ac line filters in the system. In addition, the classic DC link capacitance has also being eliminated. </p>

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21

Acharya, Anirudh Budnar, Dezso Sera, Remus Teodorescu, and Lars Einar Norum. "Modular Multilevel Converter for Photovoltaic Application with High Energy Yield under Uneven Irradiance." Energies 13, no. 10 (May 21, 2020): 2619. http://dx.doi.org/10.3390/en13102619.

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The direct integration of Photovoltaic (PV) to the three-phase Modular Multilevel Converter (MMC) without dc–dc converters results in high-efficiency PV power plant with increased energy yield. The arm power control method for the MMC further improves the extraction of available power under uneven irradiance across different phases of the MMC. However, the uneven irradiance between the sub-modules results in residual voltage that results in harmonics and unbalance components. In this paper, the effect of uneven irradiance across the sub-module of the MMC is investigated with arm power control method. A modified balancing algorithm for the arm power control of the MMC is proposed which enables balanced power to be injected into ac grid despite uneven irradiance across the sub-modules in the MMC. The modified balancing algorithm enables to keep the unbalance in the phase currents below 10% and the Total Harmonic Distortion (THD) is confined as per IEEE 519 standard.

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Khodaparast, Aryorad, Erfan Azimi, Ali Azimi, M. Ebrahim Adabi, Jafar Adabi, and Edris Pouresmaeil. "A New Modular Multilevel Inverter Based on Step-Up Switched-Capacitor Modules." Energies 12, no. 3 (February 7, 2019): 524. http://dx.doi.org/10.3390/en12030524.

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A new structure of switched capacitor multilevel inverter (SCMLI) capable of voltage boosting and with self-balancing ability is introduced in this article. This advantage is the result of a step by step rise of capacitor voltages in each module, supplied by just one DC voltage source. The proposed topology generates a sinusoidal output waveform with a magnitude several times greater than the input one. Higher output staircase AC voltage is obtained by applying a nearest level control (NLC) modulation technique. The most significant features of this configuration can be mentioned as: fewer semiconductor devices, remarkably low total harmonic distortion (THD), desirable operating under high /low frequency, high efficiency, inherent bipolar voltage production, easy circuit expansion, ease of control and size reduction of the circuit thanks to utilizing neither bulky transformer nor inductor. Moreover, the proposed SCMLI is comprehensively surveyed through theoretical investigation and a comparison of its effectiveness to recent topologies. Eventually, the operating principle of a 25-level prototype of the suggested SCMLI is validated by simulation in the MATLAB SIMULINK environment and experimental results.

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Galván, Luis, Pablo Jesús Gómez, Eduardo Galván, and Juan Manuel Carrasco. "Optimization-Based Capacitor Balancing Method with Selective DC Current Ripple Reduction for CHB Converters." Energies 15, no. 1 (December 30, 2021): 243. http://dx.doi.org/10.3390/en15010243.

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Анотація:

From its introduction to the present day, Cascaded H-Bridge multilevel converters were employed on numerous applications. However, their floating capacitor, while advantageous for some applications (such as photovoltaic) requires the usage of balancing methods by design. Over the years, several such methods were proposed and polished. Some of these methods use optimization techniques or inject a zero-sequence voltage to take advantage of the converter redundancies. This paper describes an optimization-based capacitor balancing method with additional features. It can drive each module DC-Link to a different voltage for independent maximum power point tracking in photovoltaic applications. Moreover, the user can specify the independent active power set points to modules connected to batteries or any other energy storage systems. Finally, DC current ripple can be reduced on some modules, which can extend the lifespan of any connected ultra-capacitors. The method as a whole is tested on real hardware and compared with the state-of-the-art. In its simplest configuration, the presented method shows greater speed, robustness, and current wave quality than the state-of-the-art alternative in spite of producing about 1/3 fewer commutations. Its other characteristics provide additional functionalities and improve the adaptability of the converter to other applications.

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Wang, Longjun, Guoping Ou, Zhenwei Zhou, Gang Wang, Pengfei Yu, and Zheng Zhang. "Cumulative Fatigue Damage Balancing for Modular Multilevel Converter." Energies 13, no. 18 (September 7, 2020): 4640. http://dx.doi.org/10.3390/en13184640.

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Анотація:

With many advantages, modular multilevel convert (MMC) has been extensively used in high and medium voltage power transmission projects. The thermal performance and reliability of components in MMC are key issues in system operation. However, in the current research on the reliability of MMC components, there are few methods to improve service lifetime expectancy of the components. This paper proposes a balance control algorithm, based on the cumulative fatigue damage of components, feedback to the control terminal for allocating the sub-module (SM) operating state and generating trigger pulses. Finally, the effectiveness of the proposed algorithm is verified and discussed in case studies. It is found that this algorithm is able to improve the aging degree of components in the meanwhile, the improvement in MMC reliability comes at the cost of slightly increasing capacitor voltage fluctuations and total harmonic distortion (THD). Due to the limitation of capacitor thermal performance, SM capacitor banks become a weak link in MMC reliability.

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25

Iraola, Unai, Iosu Aizpuru, Lorea Gorrotxategi, Jose Maria Canales Segade, Ander Etxeberria Larrazabal, and Inigo Gil. "Influence of Voltage Balancing on the Temperature Distribution of a Li-Ion Battery Module." IEEE Transactions on Energy Conversion 30, no. 2 (June 2015): 507–14. http://dx.doi.org/10.1109/tec.2014.2366375.

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26

Rao, T. Sanjeeva, and T. Sowjanya. "A Novel STATCOM Based on Flying Capacitor Modular Multilevel Converter." International Journal of Emerging Research in Management and Technology 6, no. 11 (June 13, 2018): 86. http://dx.doi.org/10.23956/ijermt.v6i11.51.

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Анотація:

A new static synchronous compensator (STATCOM) based on Flying Capacitor modular multilevel converter (DCM2C) is proposed in this thesis. In this converter topology the capacitor voltage is clamped by using a low power rating diode in each sub-module (SM). The quantity of voltage sensors is significantly reduced and is free from the number of voltage levels. Furthermore the voltage balancing control method becomes very simple and the capacitor voltage balance speed is fast. Based on the structure of MMC the DCM2C-STATCOM has the capability of Var compensation and negative sequence current compensation. The topology characteristics and compensation control method of DCM2C-STATCOM are investigated in this thesis. That the capacitor voltage of the proposed DCM2C-STATCOM can be well balanced and the Var and negative-sequence current compensation are effective.

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Li, Zixin, Fanqiang Gao, Fei Xu, Xun Ma, Zunfang Chu, Ping Wang, Ruifeng Gou, and Yaohua Li. "Power Module Capacitor Voltage Balancing Method for a ±350-kV/1000-MW Modular Multilevel Converter." IEEE Transactions on Power Electronics 31, no. 6 (June 2016): 3977–84. http://dx.doi.org/10.1109/tpel.2015.2501839.

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28

Fares, Ahmed M., Christian Klumpner, and Mark Sumner. "A Novel Modular Multiport Converter for Enhancing the Performance of Photovoltaic-Battery Based Power Systems." Applied Sciences 9, no. 19 (September 20, 2019): 3948. http://dx.doi.org/10.3390/app9193948.

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Анотація:

This paper introduces a novel multiport power converter with modular architecture for photovoltaic (PV)-battery based power systems. Compared to conventional centralized multiport converters, the proposed converter significantly improves the utilization of PV available energy and battery capacity as it does not require a high number of series-connected PV and battery modules. The proposed converter also eliminates the need for additional battery cell/module equalizer circuitry by being able to implement directly energy management strategies that consider the different capabilities of battery modules to ensure charge/stress balancing. This makes it a promising solution for interfacing second-life batteries or for systems that utilize batteries with a high degree of mismatch. The modularity of the proposed converter enhances system reliability and fault tolerance and reduces the power/voltage ratings of the power electronic devices. The converter modes of operation, control strategy and design considerations are discussed. A 75 V/1 kW integrated PV-battery power system prototype is built and tested to validate the concept.

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29

Teng, Fei, Dezheng Kong, Zixuan Cui, Yuan Qin, Zhenghang Hao, Na Rong, and Zhuo Chen. "DCSST Multi-Modular Equalization Scheme Based on Distributed Control." Sensors 21, no. 23 (December 4, 2021): 8125. http://dx.doi.org/10.3390/s21238125.

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Анотація:

As an important part of the DC micro-grid, DC solid-state transformers (DCSST) usually use a dual-loop control that combines the input equalization and output voltage loop. This strategy fails to ensure output equalization when the parameters of each dual active bridge (DAB) converter module are inconsistent, thus reducing the operational efficiency of the DCSST. To solve the above problems, a DCSST-balancing control strategy based on loop current suppression is presented. By fixing the phase-shifting angle within the bridge and adjusting the phase-shifting angle between bridges, the circulation current of each DAB converter module is reduced. Based on the double-loop control of the DAB, five controllers are nested outside each DAB submodule to achieve distributed control of the DCSST. The proposed control strategy can reduce the system circulation current with different circuit parameters of the submodules, ensure the balance of input voltage and output current of each submodule, and increase the robustness of the system. The simulation results verify the validity of the proposed method.

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30

Huang, Ming, and Jianhua Li. "Analysis and Design of the Split-Capacitor-Based Sub-Modules Equipped for Hybrid Modular Multilevel Converter." Energies 15, no. 7 (March 24, 2022): 2370. http://dx.doi.org/10.3390/en15072370.

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Анотація:

The hybrid modular multilevel converter (MMC) is always featured and profited by the merits of the equipped power valves. Referring to this, a novel hybrid MMC topology equipped with the split-capacitor-based sub-modules (SCSMs) on the AC side is proposed. It aims to increase the utilization of the DC bus voltage with DC fault blocking capability. Especially compared to the hybrid MMC equipped with the full-bridge-based sub-modules (FBSMs) on the AC side, smaller power losses can be achieved for the proposed hybrid MMC, due to the reason that only one semiconductor device of the SCSM is inserted into the current flow route. Structurally, the proposed converter mainly consists of the half-bridge-based sub-module (HBSM) stacks and SCSM stacks. The HBSMs located on the DC converter side of the proposed hybrid MMC are in charge of exchanging active powers, while the SCSMs located on the AC converter side are in charge of shaping the circuit waveforms. Additionally, profited by the specific structure of the SCSM, the DC fault current could be cut off by imposing inversed voltages collected from the SCSM capacitor voltages on the uncontrollable diodes of the IGBTs. For the deep study, a detailed mathematical model and modulation control of the proposed hybrid MMC are analyzed. In addition, an analysis of the balancing control for SCSMs is also provided. Finally, the simulation and experimental results are proposed to verify the effectiveness of the theoretical analysis.

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31

Kötz, R., J. C. Sauter, P. Ruch, P. Dietrich, F. N. Büchi, P. A. Magne, and P. Varenne. "Voltage balancing: Long-term experience with the 250V supercapacitor module of the hybrid fuel cell vehicle HY-LIGHT." Journal of Power Sources 174, no. 1 (November 2007): 264–71. http://dx.doi.org/10.1016/j.jpowsour.2007.08.078.

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32

Luo, Chengwei, Derong Luo, Shoudao Huang, Gongping Wu, Hongzhang Zhu, and Qianjun He. "A Novel Control Strategy for DC-Link Voltage Balance and Reactive Power Equilibrium of a Single-Phase Cascaded H-Bridge Rectifier." Energies 12, no. 1 (December 24, 2018): 51. http://dx.doi.org/10.3390/en12010051.

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Анотація:

The dc-link voltage balance and reactive power equilibrium of the cascaded H-bridge rectifier (CHBR) are the prerequisites for the safe and stable operation of the system. However, the conventional PI (Proportional-Integral) control strategy only puts emphasis on the CHBR dc-link voltage balance without taking into account its reactive power equilibrium under capacitive and inductive working conditions. For this reason, this paper has proposed a novel control strategy for the CHBR that can not only balance dc-link voltage, but also achieve reactive power equilibrium and eliminate the coupling effect between the voltage-balancing controller (VBC) and original system controller (OSC). The control strategy can achieve dc-link voltage balance and the reactive power equilibrium of the CHBR through modifying the active duty cycle by closed loop control, and adjusting the reactive duty cycle relatively according to the modifiable amount of the active duty cycle. Moreover, the strategy can eliminate the coupling effect between the VBC and OSC by the open loop control modification of the active and reactive duty cycle of any H-bridge module in CHBR. Simulations and experiments have shown that the proposed control strategy is feasible and effective in performing the CHBR dc-link voltage balance and reactive power equilibrium under all working conditions and load variations.

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Rahman, Syed, Mohammad Meraj, Atif Iqbal, and Lazhar Ben‐Brahim. "Novel voltage balancing algorithm for single‐phase cascaded multilevel inverter for post‐module failure operation in solar photovoltaic applications." IET Renewable Power Generation 13, no. 3 (December 13, 2018): 427–37. http://dx.doi.org/10.1049/iet-rpg.2018.5483.

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34

Qahouq, Jaber Abu, and Yuan Cao. "Control Scheme and Power Electronics Architecture for a Wirelessly Distributed and Enabled Battery Energy Storage System." Energies 11, no. 7 (July 19, 2018): 1887. http://dx.doi.org/10.3390/en11071887.

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This paper presents and evaluates a control scheme and a power electronics architecture for a Wirelessly Enabled and Distributed Battery Energy Storage (WEDES) system. It includes several independent battery modules (WEDES-MX modules) that transfer both power and information wirelessly to an On-Board Unit (OBU). Using wirelessly communicated State-Of-Charge (SOC) information from the WEDES-MX modules, the OBU part of the WEDES controller generates control commands and send them back to the WEDES-MX modules in order to control the amount of power/energy drawn from each WEDES-MX module and achieve SOC balancing. The presented controller also allows the WEDES system to maintain operation with a regulated bus voltage even if one or more WEDES-MX modules are removed or fail and under both balanced and unbalanced SOC conditions. The WEDES system with the presented WEDES controller when utilized in Electric Vehicle (EV) application, can allow for fast and safe exchange/swapping of WEDES-MX modules at an exchange station, home, or work and therefore potentially eliminating the range (mileage) anxiety issue that is associated with EVs’ range and the needed recharging time. The main objective of this paper is to present and evaluate the WEDES discharging controller for the WEDES system and present preliminary proof-of-concept scaled-down experimental prototype results.

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35

Lee, Jeong, Jun-Mo Kim, Kyung Ryu, and Chung-Yuen Won. "An Energy Storage System’s Operational Management and Control Method Considering a Battery System." Electronics 9, no. 2 (February 20, 2020): 356. http://dx.doi.org/10.3390/electronics9020356.

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Анотація:

Losses in energy storage systems (ESSs) result from losses in battery systems and power conversion systems (PCSs). Thus, the power difference between the input and output occurs as a loss, which is considered an operational cost. Additionally, since battery systems consist of modules, there is always a temperature difference. Even if voltage balancing is conducted, deviations between the state of health (SoH) and state of charge (SoC) always exist. Therefore, a battery characteristic should be considered in relation to the efficient operation of an ESS. In this paper, charging control is implemented based on the SoC. When errors occur in the beginning, the coulomb counting method (CCM) continues to produce errors; it also calculates the SoC through an improved equation. Thus, it can calculate the SoC by using high-accuracy initial values. Moreover, battery deterioration occurs during charging and discharging, which increases a battery’s internal resistance. This reduces the switching time to the battery cut-off voltage or constant voltage (CV) mode, so it becomes possible to calculate the SoH. Therefore, in this paper, the algorithms and equations are proposed to perform SoH operations according to the charging time that is able to reach CV after charging. A conventional battery is usually charged by using constant current (CC) charging until the voltage of the battery module reaches the cut-off area. A switch to CV then occurs when the cut-off area is reached and maintained. However, SoC-based selective charging control is carried out to prevent heat problems. In addition, the battery is charged safely and efficiently by conducting SoH prediction considering the battery thermal characteristics, which vary depending on the charging time and other characteristics. In this paper, a 3 kW ESS was produced, and the proposed algorithm’s feasibility was verified.

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36

Cao, Yuan, and Jaber Abu Qahouq. "Small-Signal Modeling and Analysis for a Wirelessly Distributed and Enabled Battery Energy Storage System of Electric Vehicles." Applied Sciences 9, no. 20 (October 11, 2019): 4249. http://dx.doi.org/10.3390/app9204249.

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Анотація:

This paper presents small-signal modeling, analysis, and control design for wireless distributed and enabled battery energy storage system (WEDES) for electric vehicles (EVs), which can realize the active state-of-charge (SOC) balancing between each WEDES battery module and maintain operation with a regulated bus voltage. The derived small-signal models of the WEDES system consist of several sub-models, such as the DC-DC boost converter model, wireless power transfer model, and the models of control compensators. The small-signal models are able to provide deep insight analysis of the steady-state and dynamics of the WEDES battery system and provide design guidelines or criteria of the WEDES controller. The derived small-signal models and controller design are evaluated and validated by both MATLAB®/SIMULINK simulation and hardware experimental prototype.

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37

Rąbkowski, Jacek, Hubert Skoneczny, Rafał Kopacz, Przemysław Trochimiuk, and Grzegorz Wrona. "A Simple Method to Validate Power Loss in Medium Voltage SiC MOSFETs and Schottky Diodes Operating in a Three-Phase Inverter." Energies 13, no. 18 (September 12, 2020): 4773. http://dx.doi.org/10.3390/en13184773.

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Анотація:

This paper presents an original method of power loss validation in medium-voltage SiC MOSFET (metal–oxide–semiconductor field-effect transistor) modules of a three-phase inverter. The base of this method is a correct description of the on-state performance of the diodes and the transistors in a PWM (pulse width modulation)-controlled inverter phase leg. Combined electro-thermal calculations are applied to precisely estimate the losses in the power devices and then, to find the suitable circuit parameters of a test circuit to emulate these conditions. A simple square-wave-controlled half-bridge with an inductive load enables the electrical and thermal stresses comparable to these in the inverter, and moreover, provided equations that confirmed the possibility of balancing the load between the diodes and the transistors. The circuit with 3.3 kV SiC MOSFETs was tested to verify the impact of selected parameters on power losses with the main focus on duty ratio. The same module was applied, in addition to an inductive load (3 × 112 μH) and two sets of DC-link capacitors (750 μF), to validate a phase leg of a 220 kVA inverter. In spite of a significantly apparent power, the active power delivered from the DC supply settled around 1 kW, which was enough to emulate 390 W of losses in two transistors and diodes.

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38

Volkov, A. G., and D. A. Sagaiko. "A research into the operation of a system of electric energy accumulation as part of a cyber-physical real time simulation facility." Power and Autonomous equipment 2, no. 4 (January 24, 2020): 209–18. http://dx.doi.org/10.32464/2618-8716-2019-2-4-209-218.

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Анотація:

Introduction: the frequency and capacity control, as well as the maintenance of electric energy systems rely on the choice of the items of equipment that comprise a particular electric energy system. Generators are the core items of equipment comprising traditional electricity systems, while in off-grid electricity systems this function is assumed by the power-driven converter equipment coupled with energy accumulation systems. The main problem of these systems consists in a fast response generated by the power-driven converter equipment to the changing environment. Excessively fast responses, given by the controllers, make the whole off-grid electricity system unstable.Methods: the resolution of the problem of an unstable off-grid electricity system requires the use of algorithms for the control over inverters and frequency converters, designed according to the principle of a virtual synchronous machine that applies voltage and frequency droops. The model of an electricity system has been produced. It has six key elements: a basic balancing inverter, two generators, lithium-oil battery simulation, an interface converter and a real time digital simulator (RTDS). The model was used to perform an experiment to implement two-way data transmission from RTDS to converting facilities and to verify the performance capability of the algorithm and the electricity system as a whole.Results and discussion: as a result of this experiment, the contact was made between RTDS, Generator 1, Generator 2 and the basic balancing inverter through interface converters. This electricity system is resilient and failure-free.Conclusion: data communication was organized between the real time module of digital simulation and Generator 2. Control commands were delivered from the digital simulation module through interface converters, and their execution monitoring was used as a feedback. The operation of grid-forming and grid-filling converters of a self-contained electricity system was stand tested at the MIPT Centre for Engineering, and optimization algorithm performance results were obtained in respect of a battery used in the course of the application of virtual synchronous machines.

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D. Ilic, Marija, and Pedro M. S. Carvalho. "From Hierarchical Control to Flexible Interactive Electricity Services: A Path to Decarbonization." International Journal of Circuits, Systems and Signal Processing 15 (October 11, 2021): 1558–70. http://dx.doi.org/10.46300/9106.2021.15.168.

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Анотація:

We propose to conceptualise electric energy systems as complex dynamical systems using physically intuitive multilayered energy modelling as the basis for systematic diverse technology integration, and control in on-line operations. It is shown that such modelling exhibits unique structure which comes from the conservation of instantaneous power (P) and of instantaneous reactive power ( _Q), (interaction variables (intVar)) at the interfaces of subsystems. The intVars are used as a means to model and control the interactive zoomed-out inter-modular (inter-area, inter-component) system dynamics. Control co-design can then be pursued using these models so that the primary control shapes intVars of its own module by using its own lowlevel detailed technology-specific model and intVar info exchange with the neighbours. As a result, we describe how the proposed approach can be used to support orderly evolution from today’s hierarchical control to a platform enabling flexible interactive protocols for electricity services. The potential for practical use of the proposed concepts is far-reaching and transparent. All that needs to be conceived is that intVar characterising any intelligent Balancing Authority (iBA) is a generalisation of today’s Area Control Error (ACE) characterising net energy balance of a Balancing Authority (BA). An iBA can be any subsystem with its own sub-objectives, such as distributed energy resources (DERs) comprising customers and grid forming microgrids; distribution systems; transmission systems; Independent System Operators (ISOs); and, ultimately, electric energy markets within large interconnection. Several industry problems are described as particular sub-problems of general interactive electricity services. These formulations help one compare models and assumptions used as part of current solutions, and propose enhanced solutions. Most generally, feasibility and stability conditions can be introduced for ensuring feasible power flow solutions, regulated frequency and voltage and orderly power exchange across the iBAs.

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Liu, Zhongxiao, Zhe Li, Jianbo Zhang, Laisuo Su, and Hao Ge. "Accurate and Efficient Estimation of Lithium-Ion Battery State of Charge with Alternate Adaptive Extended Kalman Filter and Ampere-Hour Counting Methods." Energies 12, no. 4 (February 25, 2019): 757. http://dx.doi.org/10.3390/en12040757.

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Анотація:

State of charge (SOC) estimation is a key issue in battery management systems. The challenge lies in balancing the trade-off between accuracy and computation cost. To this end, we propose an alternate method by combining the ampere-hour integral (AHI) method which has low computation cost, and the adaptive extended Kalman filter (AEKF) method, which has high accuracy. The technical viability of this alternate method is verified on a LiMnO2-LiNiO2 battery module with a nominal capacity of 130 Ah under the New European Driving Cycle (NEDC) condition. Drifts in current and voltage measurement are considered. The experimental results show that the absolute SOC error using the AHI method monotonously increases from 0% to 7.2% with the computation time of 10 s while the calculation time is obtained on a ThinkPad E450 PC with an Intel Core i7-5500U CPU @2.40 GHz and 16.0 GB RAM. The absolute SOC error of the AEKF method maintains within 3.5% with the computation time of 49 s. Therefore, the alternate method almost maintains the same SOC accuracy compared to the AEKF method which reduces the maximum absolute SOC error by 50% compared to the AHI method. Therefore, the alternate method almost has the same computation time compared with the AHI method which reduces the computation time by nearly 75% compared to the AEKF method.

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Kuder, Manuel, Anton Kersten, Jose-Luis Marques-Lopez, Julian Estaller, Johannes Buberger, Florian Schwitzgebel, Torbjörn Thiringer, et al. "Capacitor Voltage Balancing of a Grid-Tied, Cascaded Multilevel Converter with Binary Asymmetric Voltage Levels Using an Optimal One-Step-Ahead Switching-State Combination Approach." Energies 15, no. 2 (January 13, 2022): 575. http://dx.doi.org/10.3390/en15020575.

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Анотація:

This paper presents a novel capacitor voltage balancing control approach for cascaded multilevel inverters with an arbitrary number of series-connected H-Bridge modules (floating capacitor modules) with asymmetric voltages, tiered by a factor of two (binary asymmetric). Using a nearest-level reference waveform, the balancing approach uses a one-step-ahead approach to find the optimal switching-state combination among all redundant switching-state combinations to balance the capacitor voltages as quickly as possible. Moreover, using a Lyapunov function candidate and considering LaSalle’s invariance principle, it is shown that an offline calculated trajectory of optimal switching-state combinations for each discrete output voltage level can be used to operate (asymptotically stable) the inverter without measuring any of the capacitor voltages, achieving a novel sensorless control as well. To verify the stability of the one-step-ahead balancing approach and its sensorless variant, a demonstrator inverter with 33 levels is operated in grid-tied mode. For the chosen 33-level converter, the NPC main-stage and the individual H-bridge modules are operated with an individual switching frequency of about 1 kHz and 2 kHz, respectively. The sensorless approach slightly reduced the dynamic system response and, furthermore, the current THD for the chosen operating point was increased from 3.28 to 4.58 in comparison with that of using the capacitor voltage feedback.

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42

Jacques Maia de Sousa, Gean, Luiz H. T. Schmidt, Marcelo Lobo Heldwein, and Daniel Juan Pagano. "PASSIVE VOLTAGE BALANCING IN MODULAR MULTILEVEL CONVERTER DURING PRECHARGE: ANALYSIS AND DESIGN." Eletrônica de Potência 25, no. 4 (December 18, 2020): 1–12. http://dx.doi.org/10.18618/rep.2020.4.0042.

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43

Madichetty, Sreedhar, Abhijit Dasgupta, and Sambeet Mishra. "Voltage Balancing Scheme in MMC – A New Approach." International Journal of Emerging Electric Power Systems 15, no. 4 (August 1, 2014): 389–99. http://dx.doi.org/10.1515/ijeeps-2014-0096.

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Анотація:

Abstract This article proposes an online voltage balancing scheme using a new comparative reference wave modulation technique applied to modified modular multilevel converter (MMMC). Recent applications of modular multilevel converter (MMC) in high-voltage DC systems experience many problems with unbalancing of upper and lower arms, due to which circulating currents are rotating in the legs of MMC. These circulating currents pass through the arm inductors and create power loss across the inductor which consequently affects the efficiency of system. In order to overcome the unbalancing and to reduce the power losses, it proposes a new topology for existing MMC called as MMMC. Its main idea is to the balance the system voltage according to the difference between upper and lower arm currents. The upper and lower arm capacitors voltages can be well balanced by proposed technique. Compared to conventional PWM methods, this method can be realized easily. Particularly, this method has not used any kind of sorting technique, which makes it suitable for MMC with a large number of sub-modules. With experiments, the proposed method has been verified successfully.

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44

Mohammed, Ridha, Uday Alhamdany, and Nurettin Çetinkaya. "A Load Flow Analysis Method for Kufa Cement Plant." Tikrit Journal of Engineering Sciences 27, no. 3 (February 10, 2020): 1–9. http://dx.doi.org/10.25130/tjes.27.3.01.

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Анотація:

The energy needs have been enlarged extremely. The electricity power generators are utilized and distributed in the national (local) grid. Many factors can affect on national distribution grid stability, such as load flow. It is utilized to evaluate various operating states for energy generation and distribution systems. In this article, six different generators are distributed in Kufa (Iraq) cement plant based on load flow balancing. Behinds, these distributed generators work under two modes, such that island mode and regular operation. The proposed modules are analyzed using Electrical Transient Analyzer Program (ETAP) software. The achieved analysis can help to reduce the distribution grid shutdown. Furthermore, the load balancing can be achieved at both modes. Load flow analysis takes consideration for the total energy demands and losses of the system separately in order to balance load and optimize operation. The results show that the buses’ voltage drop in island mode was more than the voltage drop when the local grid connected to the national grid. The problems of drop voltages and power factor were solved.

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45

Park, Young-Hwa, Rae-Young Kim, and Yeong-Jun Choi. "An Active Cascaded Battery Voltage Balancing Circuit Based on Multi-Winding Transformer with Small Magnetizing Inductance." Energies 14, no. 5 (February 27, 2021): 1302. http://dx.doi.org/10.3390/en14051302.

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Анотація:

This paper covers the active voltage balancing method of secondary batteries. The number of applications using secondary batteries is increasing, and the batteries are normally connected in series/parallel to increase discharge cycle and power. The problem is that when there is a voltage imbalance between the cells or modules of a battery, there is a risk of an accident in the near-sighted way, shortening the life of the battery cells. Although this risk was prevented through passive balancing, this approach has limitations, including heat generation, long balancing time, and in the case of a battery that needs to be balanced between modules (or between stacks), its effectiveness decreases. Therefore, in this paper, an active cell balancing method that can overcome the limitations mentioned before is proposed. The proposed method uses a multi-winding transformer, and to increase the power density, the magnetizing inductance is decreased, and an auxiliary circuit is added. The validity of the proposed circuit was verified through mode analysis and simulation. In addition, waveforms showing the balancing performance under various conditions and the comparison results between conventional and proposed methods are given.

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46

Wang, Yingjie, Bo Yang, Huifang Zuo, Haiyuan Liu, and Haohao Yan. "A DC Short-Circuit Fault Ride Through Strategy of MMC-HVDC Based on the Cascaded Star Converter." Energies 11, no. 8 (August 10, 2018): 2079. http://dx.doi.org/10.3390/en11082079.

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Анотація:

A modular multilevel converter based high voltage direct current (MMC-HVDC) with DC fault self-clearing is adopted to deal with the DC short-circuit fault. However, the constant power load characteristic of the sub-modules causes capacitor voltages to diverge and the converter to go out of hot standby. To address this problem, a novel DC short-circuit fault ride through strategy is proposed. According to the polarities of grid voltages, the working or blockage of the upper and lower bridge arms is chosen according to six sections to obtain a cascaded star converter. The capacitor voltages of MMC sub-modules are maintained and balanced through the control similar to the cascaded star converter. Moreover, in order not to change zero crossing, a cluster balancing control method by scaling the amplitudes of the modulated waves is proposed to balance the capacitor voltages between phase clusters. The strategy also achieves the DC Bus line-to-line equipotential and no fault current generated. With the switches of two modes (normal operation and fault ride through operation) after the fault is cleared, the power transfer of MMC-HVDC can be recovered quickly. Finally, the effectiveness of the proposed fault ride through strategy is demonstrated on the 21-level MMC-HVDC simulation model in PSCAD/EMTDC.

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47

Ricco, Mattia, Laszlo Mathe, Eric Monmasson, and Remus Teodorescu. "FPGA-Based Implementation of MMC Control Based on Sorting Networks." Energies 11, no. 9 (September 11, 2018): 2394. http://dx.doi.org/10.3390/en11092394.

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Анотація:

In Modular Multilevel Converter (MMC) applications, the balancing of the capacitor voltages is one of the most important issues for achieving the proper behavior of the MMC. The Capacitor Voltage Balancing (CVB) control is usually based on classical sorting algorithms which consist of repetitive/recursive loops. This leads to an increase of the execution time when many Sub-Modules (SMs) are employed. When the execution time of the balancing is longer than the sampling period, the proper operation of the MMC cannot be ensured. Moreover, due to their inherent sequential operation, sorting algorithms are suitable for software implementation (microcontrollers or DSPs), but they are not appropriate for a hardware implementation. Instead, in this paper, Sorting Networks (SNs) are proposed due to their convenience for implementation in FPGA devices. The advantages and the main challenges of the Bitonic SN in MMC applications are discussed and different FPGA implementations are presented. Simulation results are provided in normal and faulty conditions. Moreover, a comparison with the widely used bubble sorting algorithm and max/min approach is made in terms of execution time and performance. Finally, hardware-in-the-loop results are shown to prove the effectiveness of the implemented SN.

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48

Chikurov, T. G., M. V. Kibardin, and S. L. Shirokih. "Features of Organization and Application of Active Balancing Cells with Extended Triggering Range of Shunt Circuits Keys in Ionistor Modules and Storage Devices of Joint-Stock Company “Elecond”." Vestnik IzhGTU imeni M.T. Kalashnikova 24, no. 3 (2021): 68–77. http://dx.doi.org/10.22213/2413-1172-2021-3-68-77.

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Анотація:

The solution of the problem of the deficit of voltage level for the complete unlocking of MOSFETs used as keys in the shunt circuits of the cells of the active balancing of ionistor storage devices is given. In particular, a revision of the widespread two-pole circuit of the active balancing cell of the ionistor consisting of a comparison circuit and a shunt circuit with a key on the MOSFET is presented. The relevance of the problem is confirmed by the results of the analysis of the characteristics of the key MOSFETs at the level of the unlocking voltage of 2.5...2.7 V from the output of the comparison circuit. It is shown that this voltage is not sufficient to provide the channel resistance corresponding to a fully open transistor and the flow of the specified shunt currents in the entire range of external influencing factors (VVF), especially when exposed to a reduced temperature from plus 15 to minus 60 °C. The solution presented in the paper for finalizing the circuit of the active balancing cell is that voltage boost circuits are introduced between the comparison node and the shunt circuit. Their use allows you to increase the voltage at the gate of the key MOSFET by two, three, four, etc. times, which ensures the reliable operation of the shunt circuit key for different shunt currents. A special feature of the developed cell circuits is the three-pole switching, in which an additional output is connected to the adjacent ionistor cell. This method of switching on the developed active balancing cells provides doubling of the unlocking voltage on the gate and is sufficient for reliable unlocking of the key on the MOSFET at all shunt currents at the level of the charging voltage of the ionistors in the storage device 2.5...2.7 V. For shunt currents of the order of tens of amperes, it is shown that it is necessary to switch to a quasi-four-pole switching of the developed active balancing cell due to the separation of the supply power circuits (measuring circuits) of the comparison circuit and the power buses of the level-up circuit with the shunt circuit. The methods of switching on the developed cells that allow multiplying the unlocking voltage at the gate of the key MOSFET by three, four or more times are shown. The schemes and criteria for the necessity of applying such inclusion are given. Practical testing of the developed three-pole and quasi-four-pole active balancing cells, carried out on the ionistor NEE of JSC “Elecond”, showed satisfactory stability and performance under the influence of the entire set of VVF.

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Yusof, Yushaizad, Mohd Faiz Md Adnan, Ralf Guenther, Mohd Hairi Mohd Zaman, Ahmad Asrul Ibrahim, and Afida Ayob. "Li-Ion Battery Pack Charging Process and Monitoring in Electric Vehicle." Applied Mechanics and Materials 663 (October 2014): 504–9. http://dx.doi.org/10.4028/www.scientific.net/amm.663.504.

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This paper presents the charging process procedure of Li-ion Battery pack for electric vehicle, which is implemented based on constant current and constant voltage (CC-CV) mode. All the informations regarding battery voltage level, state of charge (SOC) during charging and discharging processes, and battery temperature, is displayed on computer via battery management system (BMS). During the charging process, the BMS monitors the voltage balancing in Li-ion battery pack, as well as the cells voltage in each modules. The voltage difference between the highest voltage cell and the lowest voltage cell is very small, which validates the voltage stability and balance in battery pack during the charging and discharging processes.

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50

Abdallah, W. J. "Studies of voltage stabilization and balancing systems in energy storage modules based on supercapacitors." Journal of Physics: Conference Series 1333 (October 2019): 062001. http://dx.doi.org/10.1088/1742-6596/1333/6/062001.

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